[PATCH 3.12 037/235] dm space map metadata: fix 'struct sm_metadata' leak on failed create

From: Jiri Slaby
Date: Fri Jan 27 2017 - 05:59:24 EST

From: Benjamin Marzinski <bmarzins@xxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


commit 314c25c56c1ee5026cf99c570bdfe01847927acb upstream.

In dm_sm_metadata_create() we temporarily change the dm_space_map
operations from 'ops' (whose .destroy function deallocates the
sm_metadata) to 'bootstrap_ops' (whose .destroy function doesn't).

If dm_sm_metadata_create() fails in sm_ll_new_metadata() or
sm_ll_extend(), it exits back to dm_tm_create_internal(), which calls
dm_sm_destroy() with the intention of freeing the sm_metadata, but it
doesn't (because the dm_space_map operations is still set to

Fix this by setting the dm_space_map operations back to 'ops' if
dm_sm_metadata_create() fails when it is set to 'bootstrap_ops'.

[js] no nr_blocks test in 3.12 yet

Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
Acked-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
drivers/md/persistent-data/dm-space-map-metadata.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 8a8f06bcde60..1543f37c272a 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -773,15 +773,13 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));

r = sm_ll_new_metadata(&smm->ll, tm);
+ if (!r) {
+ r = sm_ll_extend(&smm->ll, nr_blocks);
+ }
+ memcpy(&smm->sm, &ops, sizeof(smm->sm));
if (r)
return r;

- r = sm_ll_extend(&smm->ll, nr_blocks);
- if (r)
- return r;
- memcpy(&smm->sm, &ops, sizeof(smm->sm));
* Now we need to update the newly created data structures with the
* allocated blocks that they were built from.